Deinotherium

Deinotherium
Scientific classification
Kingdom Information
Kingdom	Animalia
Phylum Information
Phylum	Chordata
Class Information
Class	Mammalia
Order Information
Order	Proboscidea
Sub-order	Deinotheroidea
Family Information
Family	Deinotheriidae
Sub-family	Deinotheriinae
Genus Information
Genus	Deinotherium
Population statistics
Conservation status	Extinct

Deinotherium (Greek: δεινός dɛinos and θηρίο thirio; "terrible beast") is the name given to three species of extinct elephant-like mammal whose chief characteristic is a pair of downward-curving tusks jutting from the lower jaw. One of the largest mammals to have walked the earth, deinothere remains have been found in Europe, Africa, and southern Asia.

Description

Deinotherium was a medium-sized to very large mammal; remains of smaller animals were partly assigned to the not universally recognized genus Prodeinotherium, which had shoulder heights of between 6.5 and 8.2 feet; Deinotherium itself had shoulder heights of 9.8 to over 13.1 feet, making it one of the largest land mammals of any time This is also reflected in the weight, which was approximately 14 tons in the largest representatives. Overall, this mammal was distinguished by an elephant-like skeleton structure with columnar but rather slender limbs, with the front legs longer than the hind legs. The foot bones showed an elephant-like short and broad design. Furthermore, the length of the cervical vertebrae was longer than that of today's elephants, giving Deinotherium the appearance of a longer neck.

The skull was very elongated and reached a length of 31 to 35 inches for smaller species and 47 to 51 inches for the large representatives. The flat forehead was lower, giving the skull a more elongated appearance versus typical elephants; the skull bones also had air-filled spaces typical of mammals to reduce the weight of the head.

Possibly the most striking feature of Deinotherium was the tusks in the elongated lower jaw, which had a downward bent shape, with the tips partially running almost vertically. In the larger species of Deinotherium, however, the curvature was also more pronounced and the tips pointed backward. The tusks were formed from the first incisor teeth, and reached a length of 4.5 feet, and were slightly compressed laterally, giving them an oval cross-section which varied between 5.1 and 6.6 inches in large animals. In sharp contrast the tusks of the upper jaw - particularly pronounced both in today's elephants as well as in numerous fossil elephants - were entirely missing in Deinotherium.

Species

• Deinotherium bozasi
• Deinotherium giganteum
• Deinotherium indicum
• Deinotherium proavum
• Deinotherium thraceiensis

Paleobiology

Lack of organic remains other than skeletons have left researchers to speculate on the animal's overall appearance and lifestyle. The partial almost horizontal position of the intermaxal bone on the upper side of the skull caused the questioning of the length of the trunk; it was speculated that in Deinotherium it did not reach the length of elephants of today, and was more of a tube than a trunk. For this reason, some researchers reconstruct a rather tapir-like short trunk. Since late representatives of Deinotherium were very large and possessed a long but comparatively short neck, the trunk must have been so long that the animals could reach much-needed drinking water when the head was lowered. Furthermore, due to the structure of the lower jaw, it is speculated that Deinotherium had a particularly pronounced lower lip.

Both the physique, especially the long, slender legs and the more mobile head, as well as the dentition, characterize Deinotherium as inhabitants of forests and floodplains. Particularly the low crown height of the molar teeth and their construction of pointed grate-like crossbars with clearly sunken valleys in between are typical for animals which prefer soft plant nutrition. Leaves, branches and bark were thus available as food sources, and that it was a browser for this food material has been confirmed by isotope investigations on the molar teeth. Deinotherium may also have lived in open, grassy areas due to climatic cooling, which would also explain their enormous size.

For a long time the function of the tusks was discussed, with a semi-aquatic way of life originally speculated, the tusks serving as digging tools in swampy forests. This was discarded due to the fact that Deinotherium would have to kneel to bring its chin low enough for the tusks to engage in digging. As leaf-eaters, they preferred bushes and tree tops as food sources; it is theorized that the animals would use their tusks to break off lower branches.

Evolutionary claims

Deinotherium represents a genus within the order of Proboscidea, within which it is placed as part of the family Deinotheriidae. According to the theory of evolution, the first smaller representative, sometimes referred to as Prodeinotherium, appeared in the early Miocene almost 22 million years ago. More than 18 million years ago, Deinotherium emigrated from Eurasia through the formation of the land bridges from Africa, reaching the Indian subcontinent. Early discoveries from large representatives of Deinotherium originate from the Middle Miocene 15 million years ago in France; in Africa the oldest finds of large animals are about 12 million years old and were also reported from Kenya. Deinotherium was spread over all three continents of the ancient world, but did not reach America.

While the small Deinotherium species had disappeared ten million years ago, the representatives in Asia survived seven million years before the late Miocene, whereas in Europe it was not until the late Pliocene. The extinction of Deinotherium is associated with the degradation of the climate at the transition from the Pliocene to the Pleistocene. Due to a stronger seasonalization of the climate and the spreading of the steppes, it was theorized that they were deprived of food. In Africa it still lived until the early Pleistocene one million years ago.

Creation science argues that Deinotherium was created with the rest of terrestrial animal life on the sixth day according to Genesis, chapter 1 of the Bible. This argument is supported by the fossil record which shows the remains of fully-developed animals; to date there have been no examples of transitional fossils found, and the evolution of Deinotherium as currently described by main stream science cannot be proven under the four steps of the Scientific method.

References

• Jeheskel Shoshani, Robert M. West, Nicholas Court, Robert J. G. Savage und John M. Harris: "The earliest proboscideans: general plan, taxonomy, and palaeoecology", In: Jeheskel Shoshani, and Pascal Tassy: The Proboscidea. Evolution and palaeoecology of the Elephants and their relatives. Oxford, New York, Tokyo, 1996